This invention deals with new and novel composite compositions and machine and contact tools, for example, metal boring tools and face mills that are manufactured from them. The tools are provided with composite structure to lighten the tools and yet retain the strength and durability of the tool. The novelty resides in the use of additives to certain fiber composite materials in the composites that make up a portion of the tool, especially tool bars.
Tool bars for use in mounting cutting tools such as most conventional boring and reaming bars are manufactured to be elongate and thin in order to machine a deep hole in a work product.
Being long and thin often leads to a bendable tool which is not easily tolerated in the industry as it creates low quality products. This bendability and lack of stiffness in the tool leads to chattering and in order to reduce this chattering, the speed of the boring tool is lessened and the feed rates are thus low, leading to low production rates. This problem has plagued the industry for a long time, and many approaches have been taken to provide tools that have high stiffness, less bendability increased dampening, and decreased weight.
For example, various shapes of cutting tools and tool bars for use in mounting the cutting tools have been developed. Many other tool bars for use in mounting cutting tools, which are made of tungsten carbide alloy and tool steel having very excellent stiffness and rigidity characteristics, have been also developed in some countries,
However, since it is difficult to machine cemented carbide, there is a disadvantage, in that, manufacturing costs of a tool bar exhibiting optimum performance become very high. Further, since the natural frequency of a boring or reaming bar is low due to high densities of tungsten carbide and tool steel, there is a limitation on improvement, of the cutting speed of the bar to remove metal and create a satisfactory finish. High weight causes several issues such as chatter, ease of use, release of the tool bars from the holder or adapter due to bending owing to the weight of the bar.
In addition, other tools, such as face mills are constructed to be heavy and durable so that they stand up to rigorous high stock removal and it would be advantageous to have such tools that could avoid or substantially avoid such adverse conditions, especially high temperature.
Fiber reinforced composites have an advantage over conventional materials in many applications because of their favorable strength to weight ratios, corrosion resistance, and unique stress coupling properties.
The method of manufacture is important in these fiber reinforced composites. The fiber orientation angle in each stiffness layer is alternated several times along the length of the component, internally, or in combination. Each time the fiber orientation angle is altered, a region of high shear is generated across the damping layer. By controlling the orientation angle, thickness, segment lengths and moduli, significant shearing occurs throughout the viscoelastic layer. Also, since the primary load path through the part is in the composite stiffness layers, the part retains high stiffness.
There are several patents dealing with cutting tools that are manufactured from tool bodies using composites. Once such device in which the body is manufactured from a carbon fiber composite in a curable epoxy resin can be found in U.S. Pat. No. 6,935,816, that issued on Aug. 30, 2005 which is incorporated herein for what it teaches about tool bars and their construction.
It has been discovered by the inventor herein that a portion of the tool can be constructed with the novel materials of this invention in order to reduce their weight yet retain their valuable properties such as strength and low chattering, that is, less or no vibration. This is especially valuable in tool bars.